Disable "Menu->Mail->Save attachment" option when mail with attachment is not selected
[BW]: [NIP] Further mail queue development.
[BW]: [Ign] Linux compile fixes.
Merge branch 'master' of https://github.com/InvictusInnovations/keyhotee

Conflicts:
	KeyhoteeMainWindow.cpp
	Mail/Mailbox.cpp
	Mail/Mailbox.hpp
Merge branch 'master' of https://github.com/InvictusInnovations/keyhotee
Missing header
Merge branch 'master' of https://github.com/InvictusInnovations/keyhotee

Conflicts:
	KeyhoteeApplication.cpp